\(\left(3x-1\right)\left(3x+2\right)-\left(3x+1\right)\left(3x+5\right)=0\)
\(\Leftrightarrow9x^2+6x-3x-2-\left(9x^2+15x+3x+5\right)=0\)
\(\Leftrightarrow9x^2+6x-3x-2-9x^2-15x-3x-5=0\)
\(\Leftrightarrow-15x-7=0\)
\(\Leftrightarrow-15x=7\)
\(\Leftrightarrow x=-\frac{7}{15}\)